From 48eb736fb71057efa7acf63f799f19e01b91e9f0 Mon Sep 17 00:00:00 2001
From: victor-sushko <victor.sushko@gmail.com>
Date: Wed, 22 Jul 2020 11:09:06 +0500
Subject: [PATCH] ExecuteScalar with column settings.

---
 .../TypeTests.cs                              | 13 +++++
 .../ClickHouseCommand.cs                      | 53 +++++++++++++++----
 2 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/src/Octonica.ClickHouseClient.Tests/TypeTests.cs b/src/Octonica.ClickHouseClient.Tests/TypeTests.cs
index 253209c..041819e 100644
--- a/src/Octonica.ClickHouseClient.Tests/TypeTests.cs
+++ b/src/Octonica.ClickHouseClient.Tests/TypeTests.cs
@@ -112,6 +112,19 @@ public async Task ReadStringWithEncoding()
             Assert.False(success);
         }
 
+        [Fact]
+        public async Task ReadStringWithEncodingScalar()
+        {
+            const string str = "АБВГДЕ";
+            var encoding = Encoding.GetEncoding("windows-1251");
+
+            await using var connection = await OpenConnectionAsync();
+            await using var cmd = connection.CreateCommand($"SELECT convertCharset('{str}', 'UTF8', 'windows-1251') AS c");
+
+            var strResult = await cmd.ExecuteScalarAsync(new ClickHouseColumnSettings(encoding));
+            Assert.Equal(str, strResult);
+        }
+
         [Fact]
         public async Task ReadGuidScalar()
         {
diff --git a/src/Octonica.ClickHouseClient/ClickHouseCommand.cs b/src/Octonica.ClickHouseClient/ClickHouseCommand.cs
index d87f638..621e7a0 100644
--- a/src/Octonica.ClickHouseClient/ClickHouseCommand.cs
+++ b/src/Octonica.ClickHouseClient/ClickHouseCommand.cs
@@ -193,41 +193,71 @@ private async ValueTask<int> ExecuteNonQuery(bool async, CancellationToken cance
 
         public override object ExecuteScalar()
         {
-            return TaskHelper.WaitNonAsyncTask(ExecuteScalar(false, CancellationToken.None));
+            return TaskHelper.WaitNonAsyncTask(ExecuteScalar(null, false, CancellationToken.None));
+        }
+
+        public object ExecuteScalar(ClickHouseColumnSettings? columnSettings)
+        {
+            return TaskHelper.WaitNonAsyncTask(ExecuteScalar(columnSettings, false, CancellationToken.None));
         }
 
         public T ExecuteScalar<T>()
         {
-            return TaskHelper.WaitNonAsyncTask(ExecuteScalar<T>(false, CancellationToken.None));
+            return TaskHelper.WaitNonAsyncTask(ExecuteScalar<T>(null, false, CancellationToken.None));
+        }
+
+        public T ExecuteScalar<T>(ClickHouseColumnSettings? columnSettings)
+        {
+            return TaskHelper.WaitNonAsyncTask(ExecuteScalar<T>(columnSettings, false, CancellationToken.None));
         }
 
         public override async Task<object> ExecuteScalarAsync(CancellationToken cancellationToken)
         {
-            return await ExecuteScalar(true, cancellationToken);
+            return await ExecuteScalar(null, true, cancellationToken);
+        }
+
+        public async Task<object> ExecuteScalarAsync(ClickHouseColumnSettings? columnSettings)
+        {
+            return await ExecuteScalar(columnSettings, true, CancellationToken.None);
+        }
+
+        public async Task<object> ExecuteScalarAsync(ClickHouseColumnSettings? columnSettings, CancellationToken cancellationToken)
+        {
+            return await ExecuteScalar(columnSettings, true, cancellationToken);
         }
 
         public async Task<T> ExecuteScalarAsync<T>()
         {
-            return await ExecuteScalar<T>(true, CancellationToken.None);
+            return await ExecuteScalar<T>(null, true, CancellationToken.None);
         }
 
         public async Task<T> ExecuteScalarAsync<T>(CancellationToken cancellationToken)
         {
-            return await ExecuteScalar<T>(true, cancellationToken);
+            return await ExecuteScalar<T>(null, true, cancellationToken);
+        }
+
+        public async Task<T> ExecuteScalarAsync<T>(ClickHouseColumnSettings? columnSettings)
+        {
+            return await ExecuteScalar<T>(columnSettings, true, CancellationToken.None);
         }
 
-        private async ValueTask<T> ExecuteScalar<T>(bool async, CancellationToken cancellationToken)
+        public async Task<T> ExecuteScalarAsync<T>(ClickHouseColumnSettings? columnSettings, CancellationToken cancellationToken)
         {
-            var result = await ExecuteScalar(reader => reader.GetFieldValue<T>(0), async, cancellationToken);
+            return await ExecuteScalar<T>(columnSettings, true, cancellationToken);
+        }
+
+        private async ValueTask<T> ExecuteScalar<T>(ClickHouseColumnSettings? columnSettings, bool async, CancellationToken cancellationToken)
+        {
+            var result = await ExecuteScalar(columnSettings, reader => reader.GetFieldValue<T>(0), async, cancellationToken);
             return (T) result;
         }
 
-        private ValueTask<object> ExecuteScalar(bool async, CancellationToken cancellationToken)
+        private ValueTask<object> ExecuteScalar(ClickHouseColumnSettings? columnSettings, bool async, CancellationToken cancellationToken)
         {
-            return ExecuteScalar(reader => reader.GetValue(0), async, cancellationToken);
+            return ExecuteScalar(columnSettings, reader => reader.GetValue(0), async, cancellationToken);
         }
 
-        private async ValueTask<object> ExecuteScalar(Func<ClickHouseDataReader, object?> valueSelector, bool async, CancellationToken cancellationToken)
+        private async ValueTask<object> ExecuteScalar(ClickHouseColumnSettings? columnSettings, Func<ClickHouseDataReader, object?> valueSelector, bool async, CancellationToken cancellationToken)
         {
             ClickHouseDataReader? reader = null;
             try
@@ -237,6 +267,9 @@ private async ValueTask<object> ExecuteScalar(Func<ClickHouseDataReader, object?
                 if (!hasAnyColumn)
                     return DBNull.Value;
 
+                if (columnSettings != null)
+                    reader.ConfigureColumn(0, columnSettings);
+
                 bool hasAnyRow = async ? await reader.ReadAsync(cancellationToken) : reader.Read();
                 if (!hasAnyRow)
                     return DBNull.Value;